Tenzen is a long-time warrior of the Iga Tsubagakure, serving as Ogen’s second-in-command for many years. Unlike Ogen, who was willing to consider peace, Tenzen harbored an intense hatred for the Kōga, believing that the Iga should eliminate their rivals completely. His loyalty to the clan is not driven by honor but by his thirst for power, as he sees war as a means to assert dominance.

When the Tokugawa shogunate reinstates the Iga-Kōga war, Tenzen takes full advantage of Oboro’s weakness as a leader, manipulating events to wrestle control away from her. Once Ogen dies, Tenzen effectively becomes the true leader of the Iga, using brutal tactics and deception to ensure the Kōga are wiped out.

However, his arrogance and cruelty ultimately lead to his downfall, as his overconfidence in his immortality blinds him to the consequences of his actions.

Tenzen has a tall, imposing figure with sharp features, long black hair, and a cold, sinister gaze. His piercing eyes and eerie smirk exude pure malice, making him an unmistakable presence among the Iga warriors.

His attire consists of traditional black Iga robes, emphasizing his authoritative status within the clan. His pale complexion and unnatural lack of scars, despite years of battle, further highlight his inhuman regenerative abilities.

As the series progresses, his expressions become more grotesque, especially when he revives from fatal injuries, revealing the horrifying nature of his immortality.

Tenzen Yakushiji is cruel, manipulative, and utterly devoid of compassion, making him one of the most despicable villains in Basilisk. He takes pleasure in violence, deception, and suffering, viewing the war between the Kōga and Iga not as a burden, but as an opportunity to assert dominance. Unlike warriors who fight for honor or duty, Tenzen fights purely for personal gain, using the conflict as a means to solidify his power and crush his enemies mercilessly. He has no loyalty to anyone but himself, often betraying his allies the moment it benefits him. His lack of empathy and complete disregard for human life make him a terrifying and remorseless enemy.

One of Tenzen’s defining traits is his arrogance, fueled by his near-immortality. Because he revives no matter how many times he is killed, he considers himself invincible, mocking his opponents and allowing himself to be “defeated” for amusement. His belief in his own superiority blinds him to true threats, leading him to underestimate his enemies, especially Gennosuke Kōga. His lust for power and control extends beyond battle, as he also indulges in sadistic pleasure, using intimidation, fear, and physical force to dominate those weaker than him. Despite his intelligence and skill, his overconfidence becomes his greatest downfall, proving that even an immortal man can be defeated by his own arrogance.

• Seizing Control of the Iga
  After Ogen’s death, Tenzen quickly takes advantage of Oboro’s weakness, asserting himself as the true leader of the Iga. He ignores Oboro’s desires for peace, instead orchestrating brutal strategies to ensure the Kōga’s complete destruction.

• Torturing and Killing Kōga Warriors
  Throughout the war, Tenzen takes particular pleasure in tormenting and killing Kōga ninja, often using psychological manipulation to break their spirits before delivering the final blow. His mercilessness and cruelty make him one of the most feared warriors in the conflict.

• Clashing with Gennosuke Kōga
  As the leader of the Iga, Tenzen views Gennosuke as his ultimate enemy, knowing that the young Kōga heir poses the greatest threat to his ambitions. However, Tenzen’s arrogance causes him to underestimate Gennosuke, leading to a series of critical miscalculations that ultimately result in his downfall.

• Final Death
  Despite his seemingly invincible immortality, Tenzen is ultimately defeated, proving that no amount of regeneration can save him from true justice. His death is one of the most satisfying moments in Basilisk, marking the end of his reign of terror.